This will be a short yet very useful tutorial. This will allow you to put more SFX than normal into your BRSAR.This will only require a program and a smashbros_sound.brsar.

First off, go and download Patch that BRSAR from http://avsys.xyz/files/software/Atlas/Patch%20that%20BRSAR%21/v1.0/Patch%20that%20BRSAR%21.exe. Second, get your BRSAR. Third, open the program "Patch That BRSAR," click on the button and select your BRSAR. Now wait a bit, and then it should say "All (insert number of BRSTM slots)" has been patched." Now, you have increased the file space in the BRSAR by some margin. Now you would be able to easily add SFX using BrawlBoxBrawlCrate or Super Sawndz and not deal with removing certain SFX.

For loading your custom BRSAR:

If you're on Dolphin, you can just extract your ISO and easily replace the old BRSAR with your new one.